Electrostatic precipitator



y 22, 1952 R. w. WARBURTON ET AL 2,604,184

ELECTROSTATIC PRECIPITATOR 4 Sheets-Sheet 5 Filed Dec. 1, 1948 7 m mm; WWW1: ii 4 m H A/ LHTW m WM m a u v W 2 ma JTTL 1 m- PM? w W M 4 m M a mm n H W 4 6H H 2 7 T u. i 2 2 M W -u||n WM LIA H &. W

Patented July 22, 1 952 ELECTROSTATIC PRECIPITATOR Ray W. Warburton,Medfield, and Frank W. Morley, Westwood, Mass, assignors to WestinghouseElectric Corporation, East Pittsburgh, Pa., a corporation ofPennsylvania Application December 1, 1948, Serial No. 62,932

12 Claims.

This invention relates to electrostatic precipitators for the removal ofsmall foreign particles, such as dust, from gases, such as air, andrelates more particularly to systems for the washing of the electrodesof such precipitators.

The electrodes of electrostatic precipitators, after periods of use,become so coated with collected matter that for emcient operation it isnecessary to clean them. A satisfactory method of cleaning theelectrodes is to wash them down with a flushing liquid, such as a lightoil. In some installations, where large volumes of gas are treated, alarge precipitator is used and one section of it is rendered inactiveand its electrodes afterwards reconnected. Its electrodes must be washedthe proper amount, and then, after washing, must be properly drainedbefore being placed back into service. The various controls must beoperated in the proper sequence and must be accurately timed. In amulti-section precipitator, much of the washing and other equipment is.common to all of the sections, and it has been found difficult toisolate one section for the washing of its electrodes withoutinterfering with the operation of the other sections. Anotherdisadvantage of a multi-section precipitator is the difficultyofadapting it to handle different volumes of gas.

This invention provides a relatively small, electrostatic precipitatorwhich can be used alone for cleaning a relatively small volume of gas,or in multiple for cleaning any desired volume of gas. Each precipitatorcontains its own equipment for automatically removing it from service,for washing its electrodes, and for returning it to service. All anattendant has to do is to actuate one control when a precipitator isready for its electrodes to becleaned, following which, its gas inletand outlet are closed, its electrodes are disconnected from their powersupply source, the pump for supplying the washing liquid to the sprayheaders is started, the headers containing the electrode washing nozzlesare moved from a parking position spaced from one end of theelectrodeswhere they are normally out of the gas stream, to the otherend thereof where the movement of the headers is reversed and they arereturned tothe parking position. When the headers reach the end of theelectrodes adjacent the parking position on their outward movement, thespray of the flushing liquid upon the electrodes is started, providedthe temperature of the liquidis above a predetermined minimum. If not,the liquid is not sprayed, and the movement of the headers is stoppeduntil the liquid reaches the proper temperature. When the headers arereturned to the parking position, they are stopped there, and a timer isstarted which provides a delay period suitable for the draining of theflushing liquid from the electrodes, following which, all controls arereturned to normal, the pump is stopped, the gas inlet and outlet areopened, the electrodes are reconnected to their power supply source, andthe precipitator is returned to service. The operations described in theforegoing are automatic, are in proper sequence, and are properly timed.

Another feature of the invention is that when an attendant initiates thedescribed operation in a particular precipitator, a light on the controlpanel is lighted, indicating that that precipitator is out of service,and a timer is started which, if the operations described in theforegoing have not been completed in the proper time, will actuate analarm signal.

, An object of the invention is to provide an improved, automaticallyoperated, control system for removing an electrostatic precipitator fromservice, for washing its electrodes, and for then restoring it toservice.

The invention will now be described with reference to the drawing, ofwhich:

Fig. 1 is a diagrammatic view illustrating the connection of severalelectrostatic precipitators embodying this invention, in multiple incommon gas inlet and outlet ducts;

Fig. 2 is a diagrammatic view illustrating the connection of theprecipitators of Fig. l to a common, flushing liquid supply source;

Fig. 3 is a diagrammatic view,'in side-elevation,

- the sprockets 35, and the chain 35.

of a portion of an electrostatic precipitator with 'More or fewerprecipitators could be used, de-

pending upon the volume ofdirty gas to be cleaned.

Fig. 2 illustrates the four precipitators with their control panel, andwith acommon fiushingg. v A common, liquid. supply pump normally closed,energizing circuit of the solenoid.

liquid sump i2.

i3 driven by an electric motor: i4, .suppliesl flushing liquid from thesump l2 to each of the 'pre-' cipitators when it is its turn to bewashed. The 7 pump 15, driven by the electric'motor i6, recir culatesthe liquid in the sump I2 through'the I cleaner [7 in which the foreignmatter therein is removed, and through the heater i8 which main tainsthe liquid at the proper temperature, which may be 180P'F. for handling.The liquid used may be a light, petroleum-base oil.

.Referring now to Figs. 3' and 4, the casing of each of theprecipitators contains the superim posed collector cells 28 with theWire ionizer electrodes 2i and the tubular ionizer electrodes 22arranged; upstream with respect .to gasxflow, thereof- The verticalspray header 24 is movable by the screws 25 threaded intoits end fitting26, horizontally between. the ionizer electrodes and the collectorcells, and has the upstream spray nozzles 21' for spraying liquid upon"the ionizer electrodes, and has the downstream, spray nozzles 28 forspraying liquid-upon the plates of the collector cells. The verticalspray header 3!) is movable bythe screws 29 threaded into its endfitting3i, and has the upstream nozzles '31 for spraying liquid upon thecollector: cells from their rear. I

The screws 25 and 29* are rotated by the electric motor 32 through thebelt 33, the pulley 34,

The inlet louvres 38 are in the'upstre'am' sideoi the; precipitatorcasing, and the outlet louvres are in the downstream side of the casing.The components described in the foregoing are disclosed in detail intheR. L. Lincoln application,

Serial No. 52,329, filed October 1, 1948;

'Normally during the gas cleaning operation,

the headers 24 and 39 are located in the park-- ing space 43 which is anopen space to one side of-tne inlet, the outlet, and the electrodes'ofthe precipitator, so as to be completely outside the gas stream beingcleaned;

' energizing circuit of the timerifil -for-the alarm -52. Atthesame timethe relay i8 is energized 4 I and pulls up its armature 19 against thecontact 88 which is in a circuit including the drain timer 53 andnormally open contacts of the switch 68, placing the timer 53 incondition for operation when the contacts of the switch 68 close. At thesame time the relay 9! is energized and pulls up its armature as againstthe contact 99 and closes the energizing circuit including normallyclosed contacts in the drain timer 53 and the thermostat Se, of the pumpmotor i 6, starting the pump if the temperature of the liquid in thesump where: the thermostat is.lecated;-is above say 180 Fl At the sametime' the rlelayiSl is energized and pulls up its armature 82 againstthe contact 33 which is in a circuit including the solenoid 55 whichactuates the valve 56 in the liquid supply piping to the headers, thethermostat and-contacts in theswitch 4 5. At the same time themelayfifiis energized and pulls up its armature-'36 awayimm the contact 81opening the ply'line'to the cylinders 69 and 6!.

The energizing circuit of the power pack 4! includes normally closedcontacts of the singlepole, double throw switch 62. V

Theinput connections to thereversingcircuit 6'! of the motor 32 includesnormally open contacts or" the switch 62, normally closed contacts ofthe switch 68, andcthe armature 92;; and the contact 93 of therelayfil.

When-the solenoid 5] is deenergized by the relaytt, it opens the valve58, causing liquid to be supplied tothe hydraulic cylinders fifl and 6iwhich then act. to close the inlet louvres 38 andthe outlet louvres 45.The closing of the inlet louvres actuates the switch 62 which opens theenergizing circuitofthe power packet, and closes the energizingcircuitto the motor reversing circuit 61, causing the motor 32 to beenergized, following which, it starts to move the headers 24 and 30 fromthe parking space towards: the collector cells. a,

When the ,headerZt reaches the left handend (facing Fig. 4 of thedrawing) of the collector cells, it .trips the switch 44- and completesthrough the thermostat 65 in. the liquidsupply piping to the headers,the-energizing circuit of the solenoid, 55 of thevalve 56, ifv thetempera.- ture of the liquid is abovev? .F., so that liquid is suppliedto the spray. nozzlesin the headers. If. the temperature is below '7 lR, the thermostatte opens the supply-circuit to the motor32 byenergizing the relay-. 9! which pulls up.:its

I armature 92 away from the'contact 93,.and opens the. energizingcircuit of the solenoid 55.. This results in the closing-of the valve 56and the prevention of the supply of liquid to thespray lect'or-cell, ittrips the switch 65 in the motor reversing circuit, causing it to closethe energizing circuit of the solenoid 94 which then retractsitsplunger" to whichthe' reversingswitch oi -the motor reversing circuitis I attached, causing-the field and armature of the motor to besoconnected as to cause the motor to reverse. The motor then moves the'-l1eader's back towards the-parkingspace 43. Whenthe header 7 Le-"reaches the switch 4 fl,-- it. again trips the switch, causing ittoopenthe circuit of the sole-F hold '55 and to thereby cut off thesupply. of liquid to'thespray-nozzles. Theheaders continue to move untilthey reach the parking space 43 where the header 24 trips the switch 68which then opens the motor reversing circuit. 6'! and stops theheadermotor 32... .1: 4 1

: At this time the switch 68 closes contacts completing the, circuit tothedrain timer 53, causing it.to'. start timing. After a period of timesufficient for the sprayed electrodes to have drained properly,ithetimer 53 first stops the pump motor [4 fordiscontinuing the building upof oil pressure, and then closes the energizing'circuit of the solenoid95 which moves the switch. 12 fromthe contact 96, and opens theenergizing circuit of the relays H, l5, [8, 8i and 85gand thus resetsthe controls in the control panel to normal, following which the valve56 is closed, the hydrauliccylinders 66 and 6| open the inletand outletlouvres, thepressure in the cylinders, being released through the drainpipe '10, the power pack 4| is again energized, the wash signal ,50 isturned off, and the alarm timer 5! is deenergized.

If for any reason the sequence of operations described in the foregoingis not completed in the proper time, the alarm 48 is actuated bythetimer 5|. V V

The timers 5| and 53' are conventional reset I timers such 'asaremanufactured by the Eagle Signal Company, and which reset their contactsto normal when deenergized. I V I Fig. 3 illustrates the switches 44, 66and 68 schematically without showing their physical locations whichareshown by Fig. 4..

The precipitator is now back in service, and the attendant can removethe key from the lock 49, andplaceit in the lock of the nextprecipitator ,tOabG. washed, following which the sequence of, operationsdescribed in, the foregoing is followed in that precipitator.

While one embodiment of the invention has been describedfor the purposeof illustration, it shouldbe understood that the invention is notlimited to the exact apparatus and arrangement of apparatus illustrated,as modifications thereof may be suggested by those skilled inthe art,without departure from the essence of the invention'. I

What is'claimed is:

l .1. An electrostatic precipitator comprising a casing having agasinlet and a gas outlet, electrodes in said casing between said inlet andoutlet, header means movable alongside said electrodes for washing same,means for supplying liquid to said header means, damper means forpreventing the flow of gas through said inlet and outlet-means for.closing said damper means, and means including means actuated when saiddamper means is closed, and including means responsive to thetemperature of the liquid supplied by said liquid supplying means tosaid header means, for starting the movement of said' header means.

2. An electrostatic precipitator comprising a casing having a gas inletand a gas outlet, electrodes in said casing between said inlet andoutlet-and inthe path of the gas stream passing therethrough, saidcasing having an open space therein, offset with respect to said inletand outlet and said electrodes, so as to be outside said gas stream andto one side of said electrodes,

I header means for washing said electrodes, said header meansbeingnormally positioned in said space, liquid supply. meansfor saidheader means, meansfor moving said header means from said space towardssaid electrodes, and means including thermostatic means responsive tothe. temperature of the liquid in said liquid supply means,andincludingmeans actuated. by said headermeans'when it moves to aposition alongside said electrodes, for actuating said liquid supplymeans to supply liquid to said header means for spraying upon saidelectrodes.

3..An.electrostatic precipitator as claimed in claim 2 in which thethermostatic means acts to stop the header moving means and the liquidsupply means when the temperature of the liquid from the liquid supplymeans is below a predetermined minimum.

4. An electrostatic precipitator comprising a casing havinga gas inletand a gas outlet, electrodes in said casing between said inlet and'outlet and in the path of the. gas stream passing therethrough, saidcasing having an open. space therein, offset with respect to said inletand outlet and' said electrodes, so as to be outsidesaid gas streamand'to one side of said electrodes, header means normally positioned insaid space, means for moving said header means from said space alongsidesaid electrodes, liquid supply means for said header means, damper meansfor preventing the flow of gas through said inlet, and outlet, means forclosing said damper means, means including means actuated by the closingof said damper means and including thermostatic means responsive to thetemperature of the liquid from said liquid supplymeans for starting saidheader moving means, and means including means actuated by said headermeans when it moves to a, position alongside said electrodes foractuating said liquid supply means to supply liquid to said header meansfor spraying upon said electrodes. I v

, 5. An electrostatic precipitator comprising a casing having a gasinlet and a gas outlet, electrodes in said casing between said inlet andoutlet and in the path of the gas stream passing therethrough, saidcasing having an open space therein, offset with respect to said inletand out. let and said electrodes, so as to be outside said gas streamand to one side of said electrodes, header means normally positioned insaid space, means formoving said header means from said space alongsidesaid electrodes, liquid supply means for said header means, damper meansfor preventing the flow of gas through said inlet and outlet, means forclosing said damper means, an electric power supply connected to saidelectrodes, means including means'actuated by the closing of said dampermeans for disconnecting said electrodes from said power supply andincluding thermostatic means responsive to the temperature of the liquidfrom said liquid supply means for starting said header moving means, andmeans including means actuated by said'header means when it moves to aposition alongside said electrodesfor actuating said liquid supply meansto supply liquid to said header means for spraying upon said electrodes.

6. An electrostatic precipitator comprising a casing having a gas inletand a gas outlet, electrodes in said casing between said inlet andoutlet and in the path of the gas stream passing therethrough, saidcasing having an open space therein, offset with respect to'said inletand outlet and said electrodes, so as to be outside said gas stream andto one side of the electrodes, header means for washing saidelectrodes,'elec trically operated valve means for supplying liquidtosaicl header means, said header means being. normally positioned insaid space, means for mov-r ingsaidheader means from, said spacetowards. said electrodes, and means including. an electric switchactuated automatically by said header means :when it moves to apositionalongside. said electrodes, for energizing said valvexmeansfor supplyingliquidto said header means for spray.- ing upon said electrodes,

7. An electrostatic precipitator comprising a casing having agas inletand a gas. outlet, damper means for preventing .the flow of gas throughsaid inlet: and outlet, means for closing said damper means, electrodesin said casing between said inlet and outlet and in the path of: the gasstream passing therethrough, said casing having an open space therein,offset with respect. to said inlet and outlet. and said electrodes, soas to be outside the gas stream and to: one sidev of the electrodes,header means for Washing said electrodes, electrically operated valvemeans. for supplying liquid to said header means, said. header meansbeing normally positioned. in saidv space, an electric motor for movingsaid headermeans, means including an electric switch actuated by theclosing of said damper means for energizing saidmotor for moving saidheader means to,- wards said electrodes, and means including an electricswitch actuated automatically by said header means when it moves to aposition in alignment with said electrodes, for: energizing said valvemeans for supplying liquid to said header means.

8. An" electrostatic precipitator comprising a casing having a gas inletand a gasoutlet, electrodes in said casing betweensaid inlet and outletand in thepath ofthe gas stream passing therethrough, said casing havingan open space therein, ofiset with respect to said inlet and outlet andsaid electrodes so as to be outside the gas stream and to one side ofsaid electrodes, header means normally positioned in said space, meansincluding an electric motor for moving said header means from said spacealongside said electrodes, liquid supply means including an electricallyoperated valve means for said header means, damper means for preventingthe flow of gas through said inlet "and outlet, means for closingsaiddamper means, means including an electric switch actuated-by'the closingof said damper means for energizing said motor; for starting said headermoving means, and means including an electric switch actuated by saidheader means when it moves to a position alongside said electrodes iorenergizing said valve means to supply liquid to said header means forspraying upon said electrodes.

9i An electrostatic precipitator comprising a casing having a gas inletand a gas outlet, electrodes in saidcasing between said-inlet and'outletand in the path, of the'gas stream passing therethrough, said casinghaving an open space therein, offsetrwith respect to, said inlet andoutlet andsaid electrodes, so as to be outside: said gas stream and toone side of, said electrodes,

' header means normally positioned in saidspaoe,

"connected to said electrodes, means including. an

electric switch actuated bythe closing of said f 8 damperv 'meansiordisconnecting said electrodes from said powersupply and for startingsaid motor, and means including an electric, switch actuated by saidheader meanswhen it moves to a position alongside said electrodes forenergi'zing said valve means to supply liquid tosaid header means forsprayingzuponsaid electrodes.

10... An electrostatic precipitator comprising a casing having. a gasinletand a gas outlet, elec-,- trodes insaidtcasing between saidinletfand outlet and in the: path of the gas stream passingtherethrough, said casing having. an: open space therein, offset with.respect! to said.- inlet and, out: let and said electrodes, so as to beoutside'the gas stream and to one side or the electrodes; header meansfor washing said electrodes, said header means: being normallypositioned in'said space,- meansincluding an electric motor for movingsaid header means from-saidspace alongside said electrodes towards theother side thereof, means including an electric switchautomaticallyoperated by said header means when it reaches the other side of said:electrodes for reversing said motor, and means including an electricswitch automatically operated bysaid header means when it returns tosaid space for stopping said motor.-

11. An electrostaticpreoipitator comprising a casing having a gas inletand a gas outlet,"electrodes in said casingbetween said inlet and outletandin the path of the gas stream passing therethrough, said casinghaving an. open space therein, olfset with respect to said inl'et andoutlet and said electrodesso as to be ou-tsidethe gas stream and to oneside of the electrodes, header means for washing saidelectrodes, said:header means being normally positioned" in said space, means includingan electric motor for: moving said header means from said spacealongside said electrodes towards the other-side thereof, liquid supplymeans including electrically operated valve means for said header means,means automatically operated by said header means when it reaches saidone side of said electrodes for energizing said valve means forsupplying liquid to said header means, means including: an electricswitch automatically operated by. said header means-whenit reachessaidiother' side of said electrodes for reversing said motor, meansincluding an electric switch automatically operated by said header meanswhen it. passesfsaid one side of said electrodes for deenergizing saidvalve means for stopping the supply of liq-uidby said liquid supplymeans to said header means, and means including an electric switchautomatically operated by said header meanswhen it returns to saidspace, for stopping said motor;

-12'. An electrostatic precipitator. comprising-a easing having a gasinlet and a gas outlet; electrodes in said casing between saidinlet and:outlet andin the, path ofthe gas streampassing therethrough, said casinghaving an open space therein, offset with respect to said inlet andoutlet and said electrodes, S0 as'to be outside the gas stream and toone side of the electrodes,,header means for washing the electrodes,said header means being normally positioned in said space, meansincluding an electric motor for moving said header meansfrom said spacealongside said electrodes towards the other side thereof means includingan electric switch automatically operated by said header means when itreaches said 7 other side of said electrodes, for reversing said anelectric switch automatieall operated by said header means when itmotor, means including period of time.

returns to said space, for stopping said motor, and timing meansenergized by said header means when it returns to said space fordeenergizing said motor for a predetermined period of time forpreventing said header means from again being moved from said space forsaid predetermined RAY w. WARBURTON. FRANK w. MORLEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number 10 UNITED STATES PATENTS Name Date Pegg Nov. 2, 1943I-I-utchison et a1. Jan. 21, 1947 Pegg Aug. 31, 1948 Penney et a1. Aug.31, 1948 FOREIGN PATENTS 7 Country Date Great Britain Mar. 1, 1937

